void main() {
  Future.wait([
    Future<String>.delayed(
      Duration(seconds: 3),
      () {
        return "异步任务_01";
      },
    ),
    Future<String>.delayed(
      Duration(seconds: 2),
      () {
        return "异步任务_02";
      },
    ),
    Future<String>.delayed(
      Duration(seconds: 1),
      () {
        return "异步任务_03";
      },
    ),
  ]).then(
    (value) => value.forEach((element) {
      print(element);
    }),
  );

  print("hello");
}
